Apparatus for producing cementitious conduits



May 14, 1963 e. D. WILLIAMSON 3,089,213

APPARATUS FOR PRODUCING CEMENTITIOUS CONDUITS 4 Sheets-Sheet 1 FiledJan. 12, 1959 INVENTOR 6445:!7' 0. d/mz/n/vsalv May 14, 1963 G. D.WILLIAMSON 3,089,213

APPARATUS FOR PRODUCING CEMENTITIOUS CONDUITS 4 Sheets-Sheet 2 M m iFiled Jan. 12, 1959 Q n n a Q c Q a m u o o o o May 14, 1963 cs. D.WILLIAMSON APPARATUS FOR PRODUCING CEMENTITIOUS CONDUITS 4 Sheets-Sheet5 Filed Jan. 12, 1959 ATE- INVENTOR. 6/1112?- 2 Mil/fl/VSO/V' y 1963 G.D. WILLIAMSON 3,089,213

APPARATUS FOR PRODUCING CEMENTITIOUS CONDUITS Filed Jan. 12, 1959 4SheetsSheet 4 IN TOR. /ziiir *gmra/v BY M MW ITTQP/Vi/i United StatesPatent 3,089,213 APPARATUS FDR PRODUCHNG (ZEMENTI'IIOUS CDNDUETS GilbertD. Williamson, Ynba (Jity, Calih, assignor to Plasti-Con Pipe (30., acorporation of California Filed Jan. 12, 1959, Ser. No. 786,291 3Claims. (Cl. 25-32) This invention relates to the manufacture ofcast-inplace pipe conduits and more particularly involves new andimproved apparatus for producing cement-itious conduits in a trench orditch.

It is one object of this invention to generally improve upon prior artapparatus, thereby improving the manufactured conduit and eliectingsubstantial savings in time and expended labors.

More specifically, it is an object of this invention to provideapparatus for producing cementitious conduits in a trench including anovel arrangement of a vibrator device in a hopper chute.

Another object is to provide apparatus for producing cementitiousconduits in a trench and having a removable hopper assembly which may bedisconnected from its supporting skid.

A further object of this invention is to provide in apparatus forproducing cementitious conduits a skid support, said skid having anarcuately shaped trailing edge portion formed with an upwardly facingconcave surface for receiving cementitious material thereon.

Another object is to provide an apparatus for producing a cementitiousconduit in a trench, including a skid having a support means for acontinuous inner casing, and also including means for biasing saidcasing toward said support means, thereby positioning said casing inspaced relation to the skid and the trench.

' Other objects of this invention will become apparent in view of thefollowing description and the accompanying drawings which disclose thisinvention.

In the drawings, forming a part of this application, and in which likeparts are designated by like reference numerals throughout the same,FIG. 1 is aside elevation of an apparatus for producing cementitiousconduits in one continuous operation;

FIG. 2 is a plan view of the apparatus of FIG. 1 with the powerequipment broken out;

FIG. 3 is a sectional view taken on lines 3-3 of FIG. 2;

FIG. 4 is a second embodiment of apparatus having a pivot connectionbetween the hopper chute and the power assembly;

FIG. 5 is a sectional view taken on lines 55 of FIG. 4;

FIG. 6 is an alternate embodiment of a roller support means for an innercasing, to be used optionally for the longitudinal rod members shown inFIG. 3;

FIGS. 7-10 are transverse sections through the apparatus of FIG. 2,corresponding section line numbers being used to identify respectivefigures;

FIGS. 11-14 are various kinds of pipe sections which may be producedwith different casing protuberances.

FIG. 15 illustrates the use of the above apparatus in combination withmeans for inflating a thin tubular casing.

Referring more particularly to FIG. 1 of the drawings, there is shownone form of improved pipe machine, gener-ally indicated by referencenumeral 1, and comprising a support skid 2, .a power supply 3, and awinch 4 with tow line 5. The arrangement of these parts is substantiallysimilar to apparatus knOWn in the prior art and operates in theconventional manner; i.e., the pipe machine is disposed in the bottom ofa trench and the tow line is anchored in advance thereof; power isdeveloped by an enice glue to drive the winch, winding up the tow lineand moving the apparatus along the bottom of the trench.

A continuous tubular casing 6 is disposed longitudinally of the trenchin advance of the machine; and as the machine moves forwardly, thecasing is supported by the skid in spaced relation to the bottom andsides of the trench. Cementitious material is deposited in a hopper 7,disposed near the rear portion of the skid, and the material is feddownwardly over and around the tubular conduit, thereby enveloping thecasing in a continuous outer layer of material. The arch-like form ofthe conduit is produced in conventional manner by an upper screed means8 which is carried rearwardly of the hopper chute. Various stages in themanufacturing process are illustrated in FIGS. 7-10 which are transversesections of the em bodiment shown in FIGS. 1-3.

One improvement over prior existing apparatus is providing the skid withan arcuately shaped trailing edge portion 9 formed with an upwardlyfacing concave surface for receiving cementitious mate-rial thereon. Itwill be noted that the discharge opening of the hopper overlies thetrailing edge 9, and will deposit the cementitious material onto theconcave surface, substantially as shown by the hidden lines. The priorart devices, which similarly utilized the gravity feed from a hopper,deposited the material directly onto the bottom of the trench. Since theearth bottom offered much resistance to the flow of material beneath thecasing, the cementitious conduit was often either incomplete orpossessed defective void spots, thus impairing the quality and strengthof the conduit. However, the smooth surface provided by the trailingedge portion greatly enhances the flow of material around and beneaththe tubular casing, thereby insuring a complete homogeneous encasementof the tubular casing.

Hopper assemblies of similar types of apparatus are formed integrallywith the skid. This construction was largely dictated by requirements ofrigidity between the hopper and skid support to insure uniform placementof the cementit-ious material in the trench. However, such aconstruction reduces the mobility of the apparatus, for, as the pipemachine approaches a roadway or other lowbridge, it must be removed fromthe trench and transported to the other side. Accordingly, there isprovided in the illustrated embodiment of FIGS. 1-3 and 9 means forremovably connecting the hopper to the skid support, and yet, there isno sacrifice in rigidity.

As best shown in FIG. 9, a hopper chute 10 is provided integrally withthe skid and has vertically inclined plate members disposed near eitherside of the trench. The chute, including its plate members, extendsupwardly from the region in which the conduit is to be produced. Thehopper 7 is correspondingly provided with vertically inclined dependingplate members which overlap the plate members of chute 10 and areremovably connected thereto by a row of bolts 11, substantially asshown.

While vibrators are conventionally utilized in pipe casting machinery toaid in the compaction of cementitious material, the improved apparatusemploys a novel arrangement of vibrating parts to enhance this tunction.FIG. 3 illustrates the specific means for securing a vibrator 12 to thehopper chute in which it is disposed. It includes a horizontal supportmember 13 extending across the chute centrally thereof, and a clampingmeans 14 for fastening the vibrator to the support member. A pluralityof armately shaped leaf spring plate members 15 are connected by theclamping means to the vibrator device and its supporting member, bestillustrated in FIGS. 3 and 9. The vibratory movement is transmitted tothe plate members and accentuated by the resilient tips of each plate,thereby forcing the cementitious material downwardly and inwardly aroundthe inner casing 6. By such arrangement, a single vibrator device isutilized to vibrate the hopper chute and also act directly upon thecementitious material, thereby obtaining maximum benefits for compactingthe material around the casing.

As indicated above, the apparatus shown supports the casing 6 in spacedrelation to the trench, and, while it is known in the prior art thatroller members 16 (FIG. 6) or, alternatively, rod members 17 (FIG. 7)may be used on the skid to accomplish this purpose, there is alsoprovided herein a means for biasing the casing toward the support means.This has been done to properly align the casing as it is fed off the endof the skid. It should be evident that there would be a strong tendencyfor the casing to be buoyed upwardly by the cementitious material,tending to raise the casing oi the support and displacing it from properalignment. Also, the inclined angle of a continuous casing supportedabove the trench bottom would tend to displace the casing. Consequently,there is provided a resiliently mounted bow member 18 having a convexsurface for making contact with the easing as it passes over the supportmeans. The bow is preferably mounted from a projecting support 19rigidly connected to the skid, and a coiled bumper spring 20 urges thebow member downwardly against the casing 6 as shown in FIG. 3. The bowis also pivoted about a horizontal axis 21, said axis being transverseto the casings line of travel. Therefore, while the bow is restrainedfrom moving longitudinally with the casing, it may pivot upwardly toaccommodate abnormal displacements or protruding obstructions on theouter surface of the casing. An alternative arrangement of a bow memberis shown in FIG. 4, and while not being as durably constructed, it wouldperform the same function.

FIGS. 4 and also illustrate a pivot connection which may be utilized toshorten the length of the skid. Inasmuch as the skid must be able totravel along the bottom of a trench the utility of the apparatus islimited by the severity of the trench curves. For, if the apparatus isextremely long it can travel only those trenches which are perfectlystraight; whereas, if the apparatus is comprised of several units, eachpivotally connected to adjacent sections, the apparatus c-an be made toturn corners. Accordingly, another form of this invention teaches a skidsupport which is sectionalized and provided with a pivot juncture.Referring more particularly to FIG. 4, there are shown sections 22 and23 of .a skid support. Each section is provided with plate members, topand bottom, the plate members of each section overlapping the respectiveplate members of the other. As illustrated, the plate members of section22 have an opening for receiving a projecting pin member therein, and apin memher is provided on the plate members of section 23 for thispurpose.

Another aspect of this invention is the formation of a cementitiousconduit about an inner casing which has a plurality of protuberances 24projecting radially from its outer surface. FIGS. 11-14 show variousforms of protuberances which may be provided for insuring rigidencasement of the casing within the cementitious conduit. In order toproduce a product of this character, the protuberances on the casing arearranged circumferentially to define continuous longitudinal portions ofcasing surface without such obstructions. Then, the support means of theskid, such as the rod member as shown in FIG. 7, will contact certain ofthe casing surfaces described and the casing will pass freely over theskid. The circumferential spacing of these surfaces likewise enables thebiasing means to engage the casing without encountering a majorobstruction such as a protuberance.

The protuberances of FIGS. 11, 12 and 13, respecively, illustrate aT-lock, rounded hobs, and a projected flange. FIG. 14 shows a coarsewrapping material, such as burlap, which also may be utilized to obtainthe desired effect. In the latter instance, it is preferable to providethe roller support means illustrated in FIG. 6 in place of the rodmembers.

The inner tubular casing 6 may be formed of metallic, plastic or pulpproducts, and each substance has been utilized at various times in theprior art to obtain a particular quality of conduit. In each instance,however, the body of the casing thus utilized has been of suflicientthick ness to support the crown portion of the cementitious material,and this is true whether a one or two step process be employed. It is,of course, desirable to use only that thickness of material which isnecessary to support the crown, since additional material is usuallywasteful and proportionately more costly.

Therefore, a method is provided which utilizes a thin plastic casing 6'which, by itself, could not sustain the crown portion of thecementitious conduit, FIG. 15. The end of the casing is initially sealedas shown to form an enclosed chamber. This may be done by fusing shutthe end of a plastic casing, or, in the case of other materials, atransverse sheet may be sealingly connected across the tubular opening.The casing is then inflated by means of an air pump 30 until sufficientfluid pressure is obtained to sustain a predetermined thickness ofcementitious material. Thereafter, apparatus 1', such as describedhereinabove but not limited thereto, can be utilized to envelop thecasing with a layer of cementitious material. As the apparatusapproaches the end of the pressurized casing, the operation is brieflyinterrupted; and after the crown portion of the cementitious materialhas sufficiently solidified, the casing is relieved of fluid pressure;then another casing is sealingly connected to the preceding one, thepressure is re-established and the operation is continued. When theprescribed length of conduit is formed, the fused end of the casing, orother closing means, is removed.

If desired, the conduit may be manufactured in sections. The beginningof each section is provided with a tube casing closure which issubsequently removed after that section is completed. Thereafter,connecting joints may be formed between the adjacent sections byconventional methods already known in the pipe manufacturing art.

The application of fluid pressure on the casing will produce someexpansion, or inflation. The amount of such expansion will dependlargely upon the kind of material, the thickness of the casing, and theoperating pressures utilized. But the fact that some expansion willresult allows the manufacture of a prestressed re-inforced cementitiousconduit. This conduit is formed in the following manner: Before applyinga source of fluid pressure to the casing, a metal cage, such as would beformed with a coiled wire, is placed therearound. Then, the fluidpressure is applied, and the casing will tend to expand, stressing thewire coils. Suflicient pressure is applied to expand the metal cageuntil it permanently deforms, thereby prestressing the metal. Thereafterthe tubular casing is enveloped with the cementitious material asdescribed above.

The above described methods, which include the steps of applying fluidpressure to a casing, have the additional advantage in that the casingwill simultaneously be tested for leaks. Any serious break in the casingwill allow fluid to escape and thereby prevent the necessary pressuresfrom being attained. The leak may be detected by introducing a coloredfluid, or other such methods as have been utilized, to trace or detectfluid flows.

It will be obvious to those skilled in the art of manufacturingcast-in-place pipe conduits that various combinations and arrangementsof apparatus may be employed, and it is to be understood that the formsof this invention herewith shown and described are to be taken aspreferred examples thereof; and, various changes in the shape, size andarrangement of certain parts may be made without departing from thespirit of this invention or the scope of the attached claims.

Having thus described my invention, What I claim and desire to secure byLetters Patent is:

1. Apparatus for producing cast-in-place conduits in a trench,comprising a skid support adapted to be disposed in and movedlongitudinally along the bottom of a trench; means on said skid forsupporting a continuous tubular casing in spaced relation to the bottomand sides of said trench, said casing having been disposedlongitudinally in advance of said skid; means mounted on the skidsupport for resiliently biasing said conduit toward said support meansincluding a resiliently mounted bow member having a convex surface formaking contact with said casing; a hopper chute mounted to said skidsupport and adjacent to but rearwardly of said bow member having adischarge opening overlying the continuous tubular casing, wherebycementitious material deposited in said hopper chute will envelop andenclose the casing; and means for advancing the skid and hopper chute inthe trench and relative to the continuous tubular casing, whereby saidcasing remains stationary relative to said trench and is resilientlyheld upon said support means by engagement with the convex surface ofsaid bow member as said hopper chute passes over and along said casingupon advancement of said skid support.

2. In apparatus for producing ca-st-inplace conduits in a trenchcomprising a skid adapted to be disposed in a trench and movedlongitudinally along the bottom surface thereof; means on said skid forsupporting a conduit form in spaced relation to the bottom and sides ofsaid trench, means defining a conduit form and adapted to be supportedupon said support means; a hopper chute mounted to said skid above saidconduit form and rearwardly of said supporting means for depositingcementitious material into said trench and enveloping said conduit form,a support member disposed within and extending longitudinally acrosssaid chute, a vibrator means disposed centrally within said hopper chuteand supported from said support member, said vibrator means including atleast one arcuately shaped leaf spring connected to a vibrator device,said leaf spring having laterally extending resilient tips on eitherside of said conduit form to accentuate vibratory movement, therebyforcing cementitious material downwardly and inwardly around the conduitform as said hopper chute is being advanced thereover and longitudinallyof said trench.

3. The apparatus of claim 1 wherein said bow member is pivotally mountedupon a horizontal axis transverse of said skid and further including aspring member urging said bow member downward against said casing andholding said casing upon said support means.

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1. APPARATUS FOR PRODUCING CAST-IN-PLACE CONDUITS IN A TRENCH,COMPRISING A SKID SUPPORT ADAPTED TO BE DISPOSED IN AND MOVEDLONGITUDINALLY ALONG THE BOTTOM OF A TRENCH; MEANS ON SAID SKID FORSUPPORTING A CONTINUOUS TUBULAR CASING IN SPACED RELATION TO THE BOTTOMAND SIDES OF SAID TRENCH, SAID CASING HAVING BEEN DISPOSEDLONGITUDINALLY IN ADVANCE OF SAID SKID; MEANS MOUNTED ON THE SKIDSUPPORT FOR RESILIENTLY BIASING SAID CONDUIT TOWARD SAID SUPPORT MEANSINCLUDING A RESILIENTLY MOUNTED BOW MEMBER HAVING A CONVEX SURFACE FORMAKING CONTACT WITH SAID CASING; A HOPPER CHUTE MOUNTED TO SAID SKIDSUPPORT AND ADJACENT TO BUT REARWARDLY OF SAID BOW MEMBER HAVING ADISCHARGE OPENING OVERLYING THE CONTINUOUS TUBULAR CASING, WHEREBYCEMENTITIOUS MATERIAL DEPOSITED IN SAID HOPPER CHUTE WILL ENVELOP ANDENCLOSE THE CASING; AND MEANS FOR ADVANCING THE SKID AND HOPPER CHUTE INTHE TRENCH AND RELATIVE TO THE CONTINUOUS TUBULAR CASING, WHEREBY SAIDCASING REMAINS STATIONARY RELATIVE TO SAID TRENCH AND IS RESILIENTLYHELD UPON SAID SUPPORT MEANS BY ENGAGEMENT WITH THE CONVEX SURFACE OFSAID BOW MEMBER AS SAID HOPPER CHUTE PASSES OVER AND ALONG SAID CASINGUPON ADVANCEMENT OF SAID SKID SUPPORT.